Wenguang Xie

Association of TLR4 Gene rs2149356 Polymorphism with Primary Gouty Arthritis in a Case-Control Study

Background The toll-like receptor (TLR)4-interleukin1β (IL1β) signaling pathway is involved in the monosodium urate (MSU)-mediated inflammation. The aim of this present study was to determine whether the TLR4 gene rs2149356 SNP is associated with gouty arthritis (GA) susceptibility and whether rs2149356 SNP impacts the TLR4-IL1β signaling pathway molecules expression. Methods and Findings The rs2149356 SNP was detected in 459 GA patients and 669 control subjects (containing 459 healthy and 210 hyperuricemic subjects). Peripheral blood mononuclear cells (PBMCs) TLR4 mRNA and serum IL1β were measured in different genotype carriers, and correlations between TLR4 gene SNP and TLR4 mRNA, IL1β were investigated. The frequencies of the genotype and allele were significantly different between the GA and control groups (P<0.01, respectively). The TT genotype was associated with a significantly increased risk of GA (OR = 1.88); this finding was not influenced by making adjustments for the components of possible confounders (adjusted OR = 1.96). TLR4 mRNA and IL1β were significantly increased in the TT genotype from acute GA patients (P<0.05, respectively), and lipids were significantly different among three genotypes in the GA patients (P<0.05, respectively). Conclusions The TLR4 gene rs2149356 SNP might be associated with GA susceptibility, and might participate in regulating immune, inflammation and lipid metabolism. Further studies are required to confirm these findings.

IL-37 inhibits the production of pro-inflammatory cytokines in MSU crystal-induced inflammatory response

Acute gouty arthritis (AGA) is an auto-inflammatory disease characterized by resolving spontaneously, which suggests that negative feedback loops control inflammatory and immunological responses to monosodium urate (MSU) crystals. By now, the molecular mechanism for spontaneous resolution of acute GA remains unclear; this study was undertaken to evaluate whether IL-37 is involved in spontaneous resolution of AGA. A total of 45 acute GA (AGA),29 non-acute GA (NAGA) male patients and 82 male health control (HC) were involved in this study, we measured IL-7 expression in the peripheral blood mononuclear cells (PBMCs), together with levels of IL-1β, IL-6, IL-10, TNF-α and TGF-β1 in the serum. Further, we either inhibited IL-37 expression in human PBMCs with siRNA or over-expressed the cytokine in human macrophages. Pro-inflammatory cytokine IL-1β, IL-6, and TNF-α expressions were significantly higher in the AGA group than in the NAGA or HC group (P < 0.05, respectively). However, anti-inflammatory IL-37, TGF-β1, and IL-10 were greater in the NAGA group than in the AGA and HC groups (P < 0.05, respectively). Expression of IL-37 in MSU crystal-treated macrophages inhibited the expression of pro-inflammatory cytokines, whereas the abundance of these cytokines increased with silencing of endogenous IL-37 in human blood cells. However, anti-inflammatory TGF-β1 and IL-10 expressions in these supernatants were unaffected by over-expression or knockdown of IL-37. Our study indicates that IL-37 is an important anti-inflammatory cytokine in AGA by suppressing the production of pro-inflammatory cytokines. Thus, IL-37 may provide a novel research target for the pathogenesis and therapy of GA.

No evidence for involvement of the toll-like receptor (TLR) 4 gene Asp299Gly and Thr399Ile polymorphisms in susceptibility to primary gouty arthritis

Previous studies demonstrated that toll-like receptor (TLR) 4 was involved in the development of autoinflammatory disease including gouty arthritis (GA). TLR4 functional gene Asp299Gly and Thr399Ile polymorphisms play a role in some autoinflammatory disease susceptibility. We undertook this study to analyze the association between the genetic polymorphisms within TLR4 gene and the susceptibility to GA in Chinese Han people. Two functional variants, Asp299Gly and Thr399Ile, in the TLR4 gene were genotyped using 5′ exonuclease TaqMan® technology from 218 male GA patients and 226 ethnically matched controls. None polymorphisms of Asp299Gly and Thr399Ile were detected in all GA cases and controls, which indicates that there is no evidence for involvement of the TLR4 gene Asp299Gly and Thr399Ile polymorphisms in susceptibility to primary GA in the Chinese Han population. Further studies with extended single nucleotide polymorphisms should be performed.

Estrogen Receptor β Signaling Induces Autophagy and Downregulates Glut9 Expression

Glut9 is highly expressed in the human kidney proximal convoluted tubular and plays a crucial role in the regulation of plasma urate levels. The gene effects were stronger among women. Our results show that 17-β-estradiol (E2) through ER (estrogen receptor) β downregulates Glut9 protein expression on human renal tubular epithelial cell line (HK2). Intriguingly, E2 does not affect the expression of Glut9 mRNA. ERβ is linked to PTEN, the PTEN gene negatively regulates the PI3K/AKT pathway, and the PI3K/AKT pathway inhibition may lead to autophagy. Further study indicates that ERβ may affect the expression of Glut9 though autophagy.

Expression of Caspase-1 Gene Transcript Variant mRNA in Peripheral Blood Mononuclear Cells of Patients with Primary Gout in Different TCM Syndromes

A large number of studies have shown that cysteinyl aspartate specific protease-1 (CASP1) played an important role in the inflammatory response of primary gout, but the decreased expression of different CASP1 transcript variant could inhibit the activation of IL-1β. Our study mainly analyzed the expression level and function of CASP1 gene transcript variant mRNA in peripheral blood mononuclear cells of patients with gout in different TCM syndromes. The expression of CASP1 gene transcript variant and IL-1β mRNA in PBMCs were detected in patients with PG [acute phase (AP: 44 cases); nonacute phase (NAP: 52 cases)] and healthy controls (HC: 30 cases) by reverse transcription-polymerase chain reaction and/or real-time quantitative polymerase chain reaction. The expressions of plasma IL-1β in patients with PG and HC were detected by enzyme-linked immunosorbent assay. Dysregulated expression of the CASP1 gene and its transcript variant, plasma proinflammatory cytokines in all patients with primary gout in different TCM syndromes, correlation analysis showed that there was negative correlation between the expression of CASP1-gamma gene transcript variant mRNA and IL-1β protein in APPG group. The study suggested that CASP1 gene and its transcript variant may play a critical role in the inflammatory response of patients with PG in different phases and TCM syndromes.

Study on the expressions of NLRP3 gene transcript variants in peripheral blood monocytes of primary gout patients

It is well-known that NLRP3 is closely related to the onset of primary gout (PG). However, the relation between NLRP3 gene transcript variants and the occurrence of PG remains unclear. This study was undertaken to evaluate whether NLRP3 gene transcript variants are involved in the occurrence of PG. A total of 44 acute phase PG (APPG), 52 non-acute phase PG (NAPPG) male patients, and 30 male health control (HC) were involved in this study. We measured NLRP3 and its transcript variants 2, 3, 4, 5, and 1 + 6 expressions in the PBMCs, together with the level of IL-1β in the serum. Further, PBMCs of HC were stimulated with MSU crystals. The levels of NLRP3, NLRP3 gene transcript variants 2, 3, 4 mRNA, and protein expressions were significantly lower in the APPG and NAPPG groups than in the HC group (P < 0.05, respectively), and IL-1β expression was significantly higher in the APPG group than in the HC and NAPPG groups (P < 0.05, respectively). Levels of IL-1β and NLRP3–4 mRNA expressions were negatively correlated with APPG group (r = − 0.2828, P = 0.0252). After stimulating PBMCs of HC with MSU crystals, levels of NLRP3, NLRP3–4 mRNA, and NLRP3 protein expressions were reduced significantly (P < 0.05, respectively), and the level of IL-1β in MSU group was increased significantly (P < 0.05). Here, we show that NLRP3–4 transcript variant may be closely related to the occurrence of PG. Thus, NLRP3–4 gene transcript variant may provide a novel target for the diagnosis and therapy of PG.

Expression of PYCARD Gene Transcript Variant mRNA in Peripheral Blood Mononuclear Cells of Primary Gout Patients with Different Chinese Medicine Syndromes

ObjectiveTo study the expression level and role of apoptosis-associated speck-like protein containing a caspase recruitment domain (PYCARD) gene transcript variant mRNA in peripheral blood mononuclear cells (PBMCs) of primary gout (PG) patients with different Chinese medicine (CM) syndromes.MethodsThe expressions of PYCARD gene transcript variant mRNA and interleukin-1β (IL-1β) mRNA in PBMCs were investigated in 96 PG patients with acute phase (APPG, 44 cases) and non-acute phase (NAPPG, 52 cases) and 30 healthy controls (HCs) by reverse transcription-polymerase chain reaction (PCR) and/or realtime quantitative PCR. PYCARD and nuclear factor-κB (p50) [NF-κB (p50)] protein was detected by Western blot in PBMCs respectively. IL-1β, IL-4 and IL-10 protein levels in plasma of HCs and PG patients were measured by enzyme-linked immuno sorbent assay.ResultsThe main CM syndromes in APPG patients were obstruction of dampness and heat syndrome (ODHS, 36.36%) and intermingled phlegm-blood stasis syndrome (IPBSS, 27.27%), while in NAPPG patients were Pi (Spleen)-deficiency induced dampness syndrome (PDIDS, 40.38%) and qi-blood deficiency syndrome (QBDS, 26.92%). It showed statistical significances of the expressions of PYCARD gene and its transcript variant mRNA, the protein of PYCARD and NF-κB (p50) and the plasma IL-1β, IL-4 and IL-10 in APPG, NAPPG, ODHS, IPBSS, PDIDS and QBDS groups, compared with the HC group respectively (P<0.05 or P<0.01). There were also significant differences of mRNA expressions of PYCARD-1 and PYCARD-2 as well as protein expressions of IL-1β, IL-4 and IL-10 among the 4 CM syndromes groups (P<0.05 or P<0.01). Correlation analysis showed positive correlation between the mRNA expressions of PYCARD-1 gene transcript variant and IL-1β in APPG patients (r=0.3088, P=0.0183).ConclusionPYCARD gene and its transcript variant may play a critical and regulative role in the inflflammatory response of PG patients with different phases and CM syndromes.